There has been an increased interest in the use of renewable oleochemical oil polyols as a substitute for petroleum-based polyols, especially for use in the production of polyurethanes. There have been several processes suggested for converting an epoxidized vegetable oil into a polyol. Each of the processes in the art converts the epoxide to the polyol by using an acid catalyst such as fluoroboric, or sulfuric acid, or acid treated clay to open the oxirane ring and then add an alcohol. Examples of fatty polyols made by acid catalyzed hydroxylation of epoxidized fatty acids include U.S.Pat. Nos. 4,508,853; 4,546,120; 4,551,517; 4,742,087; 4,826,944; 4,886,893; 5,266,714; and 5,302,626.
U.S. Pat. No. 6,107,433 discloses a process for converting vegetable oil epoxide into polyols by using a fluoroboric acid as a catalyst plus an alcohol or an alcohol and water. The problem with this process is that the fluoroboric acid is expensive, highly reactive and corrosive to the equipment, hazardous to handle, and highly exothermic, must be quenched, and its by-products present disposal problems.
U.S. Pat. No. 6,891,053 describes the use of acid treated clay to convert epoxide oil to polyol. This process has a solid waste disposal and final products must be filtered to remove the clay catalyst which is a production problem.
Unfortunately, fatty acid ester polyols formed by these current processes contain cation and anion residues. The cation and anion residues in a polyol can effect the performance of a polyurethane coating made with the polyols. For instance, the ion content can negatively change the nitrogen release characteristics of fertilizers. A polyurethane coating made from polyol containing ions may also disintegrate faster than polyurethane without ions. It is desired to have a process for producing a vegetable oil polyol in which the product is free of cation and anion residuals.
Surprisingly it has been found that the addition of a catalyst is not necessary to the formation of a fatty acid ester polyol when an in-situ epoxidized oil is used prior to a typical drying and filtering step.